Wheatstone bridge check valve arrangement

A valve device, comprising:

• a pilot valve responsive to a command signal for supplying a fluid at a command pressure to a pilot valve control port, the pilot valve having a pilot valve inlet and a pilot valve outlet;
• and
• a pilot-operated spool valve having:
• a body having a first connector and a second connector, each of the first connector and second connector being adapted for fluid communication with an external circuit;
• and
• a spool disposed for sliding movement in the body, the spool having a first end portion and a second end portion opposite the first end portion, the first end portion of the spool being in fluid communication with the pilot valve control port such that the spool is urged to move in a first direction by fluid supplied from the pilot valve at the command pressure, the spool being movable to control a main fluid flow between the first connector and the second connector through the body responsive to the command pressure when the fluid flow is a forward flow from the first connector to the second connector and when the main fluid flow is a reverse flow from the second connector to the first connector;
• and
• a valve arrangement in fluid connection with the pilot valve inlet, the pilot valve outlet, the first connector, and the second connector, the valve arrangement supplying fluid from the one of the first connector and the second connector which is at the higher pressure to the pilot valve inlet, the valve arrangement supplying fluid from the pilot valve outlet to the one of the first connector and the second connector which is at the lower pressure so that flow through the pilot valve is always from the pilot valve inlet to the pilot valve outlet without regard to which one of the first connector and the second connector is at the higher pressure.

A device, comprising:

• a pilot valve responsive to a command signal for supplying a fluid at a command pressure to a pilot valve control port, the pilot valve having a pilot valve inlet and a pilot valve outlet;
• a pilot-operated spool valve having:
• a housing defining:
• a first connector port adapted to be connected to an external fluid circuit;
• a second connector port adapted to be connected to an external fluid circuit;
• a first feedback port;
• a second feedback port;
• and
• a spool bore in fluid communication with the first connector port, the second connector port, the first feedback port, and the second feedback port;
• and
• a spool disposed for movement in the spool bore, defining:
• a first axial end face,
• a second axial end face, and
• a feedback bore communicating with the second axial end face and having variable fluid communication with the first feedback port and the second feedback port to develop a feedback pressure which varies in magnitude in dependence on the position of the spool in the spool bore when the first feedback port is supplied with a pressurized fluid;
• the first axial end face of the spool cooperating with the housing to define a command chamber in fluid communication with the pilot valve control port, the second axial end face of the spool cooperating with the housing to define a feedback chamber;
• and
• a fluid rectifier circuit in fluid communication with the pilot valve and the spool valve to route fluid from the higher pressure of the first connector port and the second connector port to the pilot valve inlet, and to return fluid from the pilot valve outlet to the lower pressure of the first connector port and the second connector port, and to route fluid from the higher pressure of the first connector port and the second connector port to the first feedback port, and to return fluid from the second feedback port to the lower pressure of the first connector port and the second connector port.

A valve network, comprising:

• a pilot-operated valve having a first connector port and a second connector port, the pilot-operated valve defining a main fluid flow path between the first connector port and the second connector port through which fluid may be directed in a first direction from the first connector port to the second connector port and may be directed in a second direction from the second connector port to the first connector port, such that when the fluid flow through the main fluid flow path in the first direction, pressure in the first connector port will be higher than pressure in the second connector port, and such that when the fluid flow through the main fluid flow path in the second direction, pressure in the second connector port will be higher than pressure in the first connector port, the pilot-operated valve further having a fluid pressure feedback circuit having a feedback inlet and a feedback outlet and developing a feedback pressure between the feedback circuit inlet and the feedback circuit outlet, the cross-sectional flow area of the main fluid flow path being controlled by interaction of the feedback pressure and a command pressure;
• a pilot valve having a pilot inlet and a pilot outlet, the pilot valve developing the command pressure in a fluid conduit connecting the pilot inlet and the pilot outlet;
• and
• a fluid rectifier circuit operable to connect the one of the first connector port and the second connector port which is at a higher pressure to both the pilot inlet and to the feedback circuit inlet, and to connect the other of the first connector port and the second connector port to both the pilot outlet and to the feedback circuit outlet.